This application includes a microfiche appendix for appendices A-D. The microfiche appendix consists of one fiche including 32 frames.
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.
1. Field of the Invention
The present invention is directed to methods and subsystems which may be provided in an intelligent bent sheet metal designing, planning and manufacturing system and the like.
2. Discussion of Background Information
FIGS. 1-3 illustrate, in a simplified view, an example conventional bending workstation 10 for bending a sheet metal part (workpiece) 16 under the control of a manually created program downloaded to various control devices provided within the workstation. The illustrated bending workstation 10 is a BM100 Amada workstation.
(a) The Hardware and Its Operation
FIG. 1 shows an overall simplified view of bending workstation 10. FIG. 2 shows a partial view of a press brake 29, positioned to perform a bend an a workpiece 16. The elements shown in FIG. 2 include a robot arm 12 having a robot arm gripper 14 grasping a workpiece 16, a punch 13 being held by a punch holder 20, and a die 19 which is placed on a die rail 22. A backgage mechanism 24 is illustrated to the left of punch 18 and die 19.
As shown in FIG. 1, bending workstation 10 includes four significant mechanical components: a press brake 29 for bending workpiece 16; a five degree-of-freedom (5 DOF) robotic manipulator (robot) 12 for handling and positioning workpiece 16 within press brake 29; a material loader/unloader (L/UL) 30 for loading and positioning a blank workpiece at a location for robot 12 to grab, and for unloading finished workpieces; and a repositioning gripper 32 for holding workpiece 16 while robot 12 changes its grasp.
Press brake 29 includes several components as illustrated in FIGS. 1-3. Viewing FIG. 3, press brake 29 includes at least one die 19 which is placed on a die rail 22, and at least one corresponding punch tool 18 which is held by a punch tool holder 20. Press brake 29 further includes a backgage mechanism 24.
As shown in FIG. 2, robot arm 12 includes a robot arm gripper 14 which is used to grasp workpiece 16. As shown in FIG. 1, material loader/unloader 30 includes several suction cups 31 which create an upwardly directed suction force for lifting a sheet metal workpiece 16, thereby allowing L/UL 30 to pass workpiece 16 to gripper 14 of robot 12, and to subsequently retrieve a finished workpiece 16 from gripper 14 and unload the finished workpiece.
In operation, loader/unloader (L/UL) 30 will lift a blank workpiece 16 from a receptacle (not shown), and will raise and move workpiece 16 to a position to be grabbed by gripper 14 of robot 12. Robot 12 then maneuvers itself to a position corresponding to a particular bending stage located within bending workstation 10. Referring to each of FIGS. 1 and 3, stage 1 comprises the stage at the leftmost portion of press brake 29, and stage 2 is located to the right of stage 1 along die rail 22.
If the first bend is to be made at stage 1, robot 12 will move workpiece 16 to stage 1, and as shown in FIG. 2, will maneuver workpiece 16 within press brake 29, at a location between punch tool 11 and die 19, until it reaches and touches a backstop portion of backgage mechanism 24. With the aid of backgage mechanism 24, the position of workpiece 16 is adjusted by robot arm 12. Then, a bend operation is performed on workpiece 16 at stage 1. In performing the bend operation, die rail 22 moves upward (along a D axis), as indicated by the directional arrow A in FIG. 2. As punch tool 18 and die 19 simultaneously contact workpiece 16, so that workpiece 16 assumes a relatively stable position within press brake 29, gripper 14 will release its grasp on workpiece 16, and robot 12 will move gripper 14 away from workpiece 16. Press brake 29 will then complete its bending of workpiece 16, by completing the upward movement of die 19 until the proper bend has been formed.
Once die 19 is engaged against punch tool 18, holding workpiece 16 in its bent state, before disengaging die 19 by lowering press brake 29, robot arm 12 will reposition its robot arm gripper 14 to hold workpiece 16. Once gripper 14 is holding workpiece 16, die 19 will be disengaged by releasing press brake 29. Robot 12 then maneuvers and repositions workpiece 16 in order to perform the next bend in the particular bend sequence that has been programmed for workpiece 16. The next bend within the bend sequence may be performed either at the same stage, or at a different stage, such as stage 2, depending upon the type of bends to be performed, and the tooling prided within press brake 29.
Depending upon the next bend to be performed, and the configuration of workpiece 16, the gripping position of gripper 14 may need to be repositioned. Repositioning gripper 32, shown in FIG. 1, is provided for this purpose. Before performing the next bend, for which repositioning of robot gripper 14 is needed, workpiece 16 will be moved by robot 12 to repositioning gripper 32. Repositioning gripper 32 will then grasp workpiece 16 so that robot gripper 14 can regrip workpiece 16 at a location appropriate for the next bend or sequence of bends.
(b) The Control System
The bending workstation 10 illustrated in FIG. 1 is controlled by several control devices which are housed separately, including an MM20-CAPS interface 40, a press brake controller 42, a robot controller 44, and a load/unload unit controller 46. Press brake controller 42 comprises an NC9R press brake controller, and robot controller 44 comprises a 25B robot controller, which are each supplied by Amada. Each of press brake controller 42 and robot controller 44 have their own CPU and programming environments. Load/unload unit controller 46 comprises a stand alone Programmable Logic Controller (PLC), and is wired to respective consoles provided for press brake controller 42 and robot controller 44.
Each of controllers 42, 44, and 46 has a different style bus, architecture, and manufacturer. They are coordinated primarily by parallel I/O signals. Serial interfaces are provided for transporting bending and robot programs to the controllers, each of which is programmed in a different manner. For example, logic diagrams are used to program the PLC of the load/unload controller 46, and RML is used to program robot controller 44.
(c) The Design/Manufacture Process
The overall design/manufacture process for bending sheet metal includes several steps. First, a part to be produced is typically designed using an appropriate CAD system. Then, a plan is generated which defines the tooling to be used and a sequence of bends to be performed. Once the needed tooling is determined, an operator will begin to set up the bending workstation. After the workstation is set up, the plan is executed, i.e., a workpiece is loaded and operation of the bending workstation is controlled to execute the complete sequence of bends on a blank sheet metal workpiece. The results of the initial runs of the bending workstation are then fed back to the design step, where appropriate modifications may be made in the design of the part in view of the actual operation of the system.
In the planning step, a plan is developed for bending workstation 10 in order to configure the system to perform a sequence of bending operations. Needed hardware must be selected, including appropriate dies, punch tools, grippers, and so on. In addition, the bending sequence must be determined, which includes the ordering and selection of bends to be performed by bending workstation 10. In selecting the hardware, and in determining the bending sequence, along with other parameters, software will be generated to operate bending workstation 10, so that bending workstation 10 can automatically perform various operations of the bending process.
A plan for a BM100 bending workstation includes generated software such as an NC9R press brake program and a 25B RML robot program. Each of these programs may be created with the use of an initial part design created from a CAD system. Both the robot program and the bending program must be developed manually, and are quite labor-intensive. Previously developed programs are classified by the number of bends and/or by the directions of the bends. Engineers examine each part style to determine if previously developed and classified program may be used or whether a new program must be written. However, since each classified program typically supports only a narrow range of acceptable part dimensions, new programs must frequently be written by the engineers. The final RML robot program, when complete, is compiled and downloaded by the MM20-CAPS system 40 to robot controller 44. The bending program is entered and debugged on a control pendant provided on press brake controller 42. After entering the robot and bending programs into the system, an operator performs several manual operations to walk the system through the several operations to be performed. For example, an operator will manually operate a hand-held pendant of the robot controller to manually move the robot to the loading and unloading positions, after which the interface console 40 will store the appropriate locations into the final RML program to be compiled and downloaded to robot controller 44. In addition, in producing the bending program, the operator may control the system to follow the planned bend sequence, in order to determine the values for the backgage position (L axis) and the die rail position (D axis).
(d) Intelligent Manufacturing Workstations
Various proposals have been made in order to overcome many of the drawbacks with prior systems such as the BM100 Amada bending workstation, and research has been conducted in the area of intelligent manufacturing workstations. Some proposed features of intelligent sheet metal bending workstations included features such as open architecture, including open system configurations and distributed decision making, and enhanced computer aided design and geometric modeling systems.
A paper entitled xe2x80x9cIntelligent Manufacturing Workstationsxe2x80x9d was presented at the 1992 ASME Winter Annual Meeting regarding Knowledge-Based Automation of Processes on Nov. 13, 1992, by David Alan Bourne; the content of the Paper is expressly incorporated herein by reference in it entirety. In the Paper, an intelligent manufacturing workstation is defined as a self-contained system that takes a new design for a part and manufactures it automatically. The process is stated to include automated setup, part programming, control, and feedback to design.
The Paper discusses several components of an coverall intelligent manufacturing workstation, including features such as open architecture the use of software modules that communicate via a query-based language, part design, operations planning, workstation control, and geometric modeling.
(1) Open Architecture
It has been recognized that an effective intelligent manufacturing workstation should have open software, open controller and open mechanism architecture. That is, a machine tool user operating such a workstation should be able to add onto the software, the controller, and the mechanism architectures of the workstation in order to improve their functions.
(2) Software Modules Using Query-Based Language
Software modules have been suggested, in the above-noted paper by David Bourne, for use in an intelligent manufacturing workstation. Such modules would be split along knowledge boundaries which have been defined in industrial practice, including, e.g., tooling, operations, programming, planning and design. The software modules would be responsible for understanding commands and data specifications, and for answering questions in their own area of specialty. A particular module might be configured to request information from other modules so that it has adequate information to solve its designated problems, to communicate in a standard language, and to work on several problems at once. In addition, each module would know which other module to ask for information and provide assistance in formulating a question for the receiving module. The general software architecture proposed in the above-noted Paper is illustrated in FIG. 4. The proposed architecture includes a designer 50, a bend sequence planner 52, a module 54 for sequence planning, execution and error handling, a modeler 56, a module 58 for sensor interpretation, and modules 60, 62 for process control and holding, and fixturing. Each of the modules for sensor interpretation 58, process control 60, and holding and fixturing 62 are coupled to external machine and sensor drives 64. A control subsystem 68 is formed by several of the modules, including sequence planning, execution and error handling module 54, modeler 56, and the modules for sensor interpretation 58, process control 60 and holding and fixturing 62. Control subsystem 68 is shown as being implemented within a Chimera operating system. All of the modules may be connected to other factory systems 66, including, e.g., systems for scheduling, operations, and process planning.
(3) Design Tools
Experimentation has been conducted with design tools that constantly manage the relationship between a stock part and a final part as it is applied to sheet metal bending, as noted in the above-referenced Paper, and as disclosed by C. Wang in xe2x80x9cA Parallel Designer for Sheet Metal Parts,xe2x80x9d Mechanical Engineering Master""s Report, Carnegie Mellon (1992), the content of which is expressly incorporated herein by reference in its entirety. The design information, which may be described in 3D, or as a 2D flat pattern, is automatically maintained (in parallel) with another representation of the developing part. In this way, a connection between each of the features of the initial stock part and the final part is maintained.
(4) The Planning System
Once the design is complete, a planner typically then produces a plan which will later be used to execute the manufacturing process. The plan includes several instructions regarding the sequencing of machine operations to produce the desired part. An optimal plan will result in a reduction of setup time, a reduction in the existence of scrap after production of the parts, an increase in par quality, and an increase in production rate. To promulgate such advantages, the above-noted Paper recommends that as much specific knowledge as possible be separated from the planner so that the planner can be easily adapted to different machines and processes. A xe2x80x9cquery-basedxe2x80x9d planning system is thus proposed which shifts the emphasis of the planner to asking expert questions, rather than attempting to act as a self-contained expert.
(5) Workstation Control
The above-noted Paper proposes that the controller use an off-the-shelf engineering UNIX workstation as the core computing resource. The workstation may include in its back-plane an extension rack of special-purpose boards and an additional CPU that runs with a real-time version of the UNIX operating system, called CHIMERA-II. See, e.g., STEWART et al., Robotics Institute Technical Report, entitled xe2x80x9cCHIMERA II: A Real-Time UNIX-Compatible Multiprocessor operating System for Sensor Based Control Applications,xe2x80x9d Carnegie Mellon, CMU-RI-TR-89-24 (1989), the content of which is expressly incorporated by reference herein in its entirety.
(6) Geometric Modeling
Geometric modeling is an important component in intelligent machining workstations. Several modelers have been experimented with during a project in the Robotics Institute at Carnegie Mellon University. A geometric modeler called xe2x80x9cNOODLESxe2x80x9d has been proposed for use as a modeler in an intelligent manufacturing workstation. The NOODLES modeler is discussed by GURSOZ et al., in xe2x80x9cBoolean Set operations on non-manifold boundary representation objects,xe2x80x9d in Computer Aided Design, Butterworth-Heinenmann LTD., Vol. 23, No. 1, January, 1991, the content of which expressly incorporated by reference herein in its entirety The NOODLES system makes far fewer assumptions about what constitutes valid edge topologies, and thus overcomes problems with other modeling systems, which would enter into infinite loops when the edge topology of a geometric model would violate system assumptions.
6. Term Definitions
For purposes of clarification, and to assist readers in an understanding of the present invention, the following terms and acronyms used herein are defined.
bending apparatus/bending workstationxe2x80x94a workstation or apparatus for performing modern sheet metal working functions, including bend operations.
bending sheets of malleable materialxe2x80x94working of sheets of malleable material, such as sheet metal, including, and not limited to, up-action air bending, V bending, R bending, hemming, seaming, coining, bottoming, forming, wiping, folding type bending, custom bending, and so on.
operations planxe2x80x94a sequence of operations to be performed by a part forming apparatus in order to form a finished part from a piece of unfinished material. In the context of bend sequence planning, an operations plan (bend sequence plan) comprises a sequence of operations to be performed by a bending apparatus for bending workpieces comprising sheets of malleable material, the sequence of operations including a bend sequence which includes all of the bends needed to form a finished bent workpiece.
subplanxe2x80x94a portion of a complete operations plan. In the context of bend sequence planning, a subplan comprises a part of the information needed to set up and/or control a bending workstation/apparatus.
In view of the above, the present invention, through one or more of its various aspects and/or embodiments, is thus presented to bring about one or more objects and advantages, such as those noted below.
Generally speaking, it is an object of the present invention to provide an intelligent bending workstation environment/system which may be easily upgraded and integrated with additional or alternate hardware and software modules. A further object is to provide such a system which can be used to economically produce very small batch sizes (of one or more workpieces) with high quality, and in a short amount of time. In addition, an object is to provide such a system that is flexible and that is able to accommodate new and different part styles in the design and manufacture process. The system of the present invention is intended to operate efficiently in large volume production, and to learn from initial production runs in order to maximize efficiency.
An additional object of the invention is to maintain quality of the produced parts throughout the process, and to avoid errors and collisions during execution of the process by the bending workstations. It is a further object of the present invention to provide an intelligent sheet metal bending workstation which makes small batches of sheet metal parts from CAD descriptions. In this regard, a process planner is provided that selects the necessary hardware (e.g., dies, punches, grippers, sensors) to be utilized by the bending workstation, determines bending sequences, and generates the necessary software to operate the bending machine.
It is a further object of the present invention to provide such an intelligent, automated bending workstation which first generates a process plan and then executes the generated plan using a real-time sensor-based control method. When the process is executed, the results thereof may be recorded for later review, so that the process may be refined to make it more efficient, and to reduce the occurrence of errors during execution.
An additional abject of the present invention is to provide a system which can produce a plan for bending a sheet metal workpiece, in which the smallest number of tooling stages will be utilized to make the part. A further object is to provide a system that will efficiently and automatically produce the plan to be utilized by the bending workstation, set up the workstation, and execute the plan.
The present invention, therefore, is directed to several systems, methods and sub-components provided in connection with a system for generating a plan which comprises a sequence of operations to be performed by a bending apparatus for bending workpieces comprising sheets of malleable material. The bending apparatus has a gripper for gripping a workpiece while performing a bend, and the sequence of operation includes a set of N bends for forming a finished workpiece from a stock sheet of malleable material. The system includes a proposing mechanism for proposing, for an mth operation within the sequence of operations, a plurality of proposed operations including a plurality of proposed bends to be performed by the apparatus. In addition, the system includes a subplan mechanism for providing a proposed subplan that accompanies each proposed bend, and a generating mechanism for generating a plan including a sequence of bends from a first bend through an Nth bend, by choosing each bend in the sequence of operations based upon the proposed bends and the proposed subplan that accompanies each proposed bend.
The proposing mechanism may be designed so that it proposes bends among the complete set of N bends that are still remaining, or proposes bends among the complete set of bends that a still remaining less bends block due to constraints. In addition, the proposing mechanism may propose, for an mth operation, a repositioning of a gripper""s hold on the workpiece.
In accordance with a specific aspect of the invention, the generated plan further includes at least part of the proposed subplans that accompany the chosen bends. The system may further include a mechanism for representing the mth operation as an mth level of a search tree. The proposed subplans may include setup and control information for the bending apparatus, and may further comprise final locations on the workpiece at which the gripper will grip the workpiece while performing the bends of the bend sequence. The proposed subplans may further include ranges of locations on the workpiece at which the gripper can grip the workpiece while performing the bends of the bend sequence. In addition, the proposed subplans may comprise: numbers representing a predicted number of repositionings of the gripper needed to complete the sequence of bends, indications that the next bend in the sequence cannot be performed unless the gripper is first repositioned, and/or locations on the workpiece at which a repositioning gripper (i.e., a repo gripper) will grip the workpiece while performing a repositioning operation. Additionally, the proposed subplans may include: tooling stages to be utilized to perform the bends in the bend sequence, positions along a tooling stage at which the workpiece will be loaded into the bending apparatus in order to perform the bends, and/or motion plans for maneuvering around tooling stages in performing the bends.
In accordance with a further aspect of the system, an estimating device is provided for estimating a cost to be associated with each proposed bend. In this regard, the generating mechanism may generate a plan including a sequence of bends from a first through an Nth bend, by choosing each bend in the sequence of operations based upon the proposed bend, the proposed subplan that accompanies each proposed bend, and the estimated costs associated with each proposed bend. The estimated costs associated with an nth bend in the sequence of N bends may comprise a k cost calculated based upon an estimated amount of time it will take the bending apparatus to complete one or more operations of the bend. The estimated costs associated with an nth bend in a sequence of N bends may comprise an h cost calculated based upon an estimated total amount of time it will take the bending apparatus to complete one or more operations of each of the rest of the bends in the bend sequence that follow the nth bend.
The one or more operations of the bend which will be timed in order to calculate the k and h costs may comprise moving the workpiece from a tooling stage location of a preceding bend to a tooling stage location of the given bend. The one or more operations of a given bend may also comprise installing, when setting up the bending apparatus, an additional tooling stage needed to perform the given bend. The one or more operations of a given bend may also comprise repositioning of the gripper""s hold on the workpiece before performing the given bend.
In accordance with a further aspect of the present invention, the proposing mechanism and the generating mechanism collectively comprise a bend sequence planning module, and the subplan mechanism and the estimating mechanism collectively comprise a plurality of expert modules. The expert modules may each operate the subplan mechanism and the estimating mechanism when the proposing mechanism proposes a proposed operation for performance as the mth operation within the sequence of operations. The plurality of expert modules may comprise a holding expert module which is capable of operating the subplan mechanism to provide a proposed subplan, including information regarding a location on the workpiece at which the gripper can hold the workpiece while performing the bends of the bend sequence. The plurality of expert modules may comprise a holding expert module which is capable of operating the estimating mechanism to estimate a holding cost, calculated based upon whether a gripper""s hold on the workpiece is to be repositioned before performing a given bend. In addition, the plurality of expert modules may comprise a tooling expert module which is capable of operating the subplan mechanism to provide a proposed tooling subplan that includes information regarding a position along a tooling stage at which the workpiece will be loaded into the bending apparatus in order to perform a given bend. The tooling expert may also be capable of operating the estimating mechanism to estimate a cost based upon an amount of time to install, when setting up the bending apparatus, an additional tooling stage needed to perform a given bend. The motion expert module may also be capable of operating the estimating mechanism to estimate a cost based upon a calculated travel time for moving the workpiece from a tooling stage location of one bend to a tooling stage location of a next bend.
In accordance with an additional aspect of the invention, the bend sequence planning module may be capable of querying each of the expert modules for a subplan and estimated costs. In addition, each of the expert modules may be capable of responding to a query by returning a savelist to the bend sequence planning module, whereby the savelist includes a list of names of attributes, and values respectively corresponding to the attributes, to be saved by the bend sequence planning module.
As a further aspect of the invention, the system includes a prioritizing mechanism for prioritizing proposed bends in accordance with bend heuristics determined based upon the geometry of the workpiece. The generating mechanism may generate a plan, including a sequence of bends from a first through an Mth bend, by choosing each bend in the sequence of operations based upon the prioritized proposed bends and the proposed subplan that accompanies each proposed bend. The prioritizing mechanism may be provided with a mechanism for discounting an estimated cost of a bend having a high priority and increasing an estimated cost for a bend having a low priority.
In accordance with a further aspect of the invention, a determining mechanism may be provided for determining the time needed for, and the feasibility of, producing one or more parts with the bending apparatus based upon the generated plan. In addition, the system may be provided with a mechanism for performing calculations of the costs of producing a given batch of parts, based upon the time determined by the determining mechanism. In addition, or in the alternative, the system may be provided with a mechanism for redesigning the part based upon the time and the feasibility determinations made by the determining mechanism. The system may be further provided with a mechanism for scheduling manufacturing with the bending apparatus depending upon the determined amount of time for producing one or more parts.
In addition to the above-described system, the present invention is further directed to a computerized method for selecting a gripper for holding a workpiece. The gripper is selected for use in a bending apparatus for bending unfinished workpieces comprising sheets of malleable material. The method includes reading information describing the geometry of a library of grippers to be chosen from, forming a set of available grippers excluding grippers that have certain undesired geometric features, and choosing a gripper from a set of available grippers. The gripper is chosen as a function of the width of the gripper, the length of the gripper, and the knuckle height of the gripper. The gripper may include a gripper for holding the workpiece while loading and unloading the workpiece into and from a die space of the bending apparatus. In this regard, the method may include a step of predicting, for each gripper within the set of available grippers, a repo number equal to an estimated number of times the bending apparatus will need to change the position at which the gripper is holding the workpiece in order to perform a complete sequence of bending operations on the workpiece. The smallest predicted repo number is then determined, and the set of available grippers is adjusted to include the available grippers having a repo number equal to the smallest predicted repo number, before choosing (from among the set of available grippers) a gripper as a function of the gripper""s width, length, and knuckle height.
The gripper may alternatively comprise a repo gripper for holding the workpiece while a robot changes its grip on the workpiece. In this regard, the method may be further provided with a step of constructing data representations of the respective intermediate shapes of the workpiece when repo operations are to be performed by the bending apparatus, and utilizing the intermediate shapes to determine which grippers are excluded from the set of available grippers. The grippers that cannot securely grasp the workpiece, considering all of the constructed intermediate shape representations, are excluded from the set of available grippers.
In addition to the above-described system and method, the present invention is further directed to a computerized method for determining a location at which a gripper can hold a malleable sheet workpiece while a bending apparatus performs an mth operation on the workpiece. The bending apparatus performs a sequence of operations, including the mth operation, in accordance with a bending plan. The sequence of operations includes a sequence of bends from a first bend through an Nth bend, and the shape of the workpiece changes to several intermediate shapes as the bending apparatus progresses through the sequence of bends. A set of topographic representations is formed by repeatedly generating, along edges of the workpiece, as a variable i is varied, a graphic representation of areas on the workpiece within which the gripper location can be without hindering performance of an ith operation. A determination is made as to whether or not the performance of the ith operation will be hindered by taking into consideration the intermediate shape of the workpiece when the ith operation is performed. The method further includes the step of determining the intersection of all the geographic representations within the set to thereby determine the areas common to the given plurality of operations in the sequence of operations. The mth operation may include changing a robot""s grip on the workpiece between bends in the sequence of bends, and/or performing a bend within the sequence of bends.
In addition to the above, the present invention may be directed to a computerized method for selecting tooling to be used in a bending apparatus for bending a workpiece comprising a sheet of malleable material. The tooling includes at least a die and a punch, and the bending apparatus performs, utilizing the selected tooling, a sequence of operations comprising a sequence of bends from a first bend through an Nth bend. The method comprises steps of reading information describing in the geometry of dies and punches, and forming sets of feasible dies and punches excluding dies and punches that have an insufficient force capacity to bend the workpiece and that are incapable of forming desired bends in the workpiece resulting in desired angles and desired inside radii. In addition, the method includes a step of choosing an appropriate die and appropriate punch that most closely satisfies force, bend angle, and inside radii requirements, excluding punches that will likely collide with the workpiece as determined by failure of a geometric collision test.
The geometric collision test may be performed by modeling a finished 3D workpiece and, for each bend in the sequence of bends, aligning the modeled finished 3D workpiece between a model of each feasible punch and a model of a chosen die.
In addition to the above, the present invention may be directed to a computerized method for determining a layout of tooling stages along a die rail of a bending apparatus. The bending apparatus is adapted to bend workpieces comprising sheets of malleable material, by performing a sequence of operations comprising a sequence of bends from a first bend through an Nth bend. The method includes a step of deciding on an arrangement of a plurality of stages along the die rail and calculating lateral limits based upon the amount by which the workpiece extends beyond a side edge of a tooling stage for the bends of the sequence of bends. In addition, the method includes determining a largest lateral limit for each side of the stage, and spacing adjacently arranged stages to have a gap between adjacent side edges that is greater than or equal to the larger of the determined largest lateral limits of the adjacent side edges.
In addition to the above-described system and methods, the present invention may be directed to a system for generating a plan and for controlling a bending apparatus. As described above, the plan comprises a sequence of operations to be performed by the bending apparatus, and the bending apparatus is adapted to bend workpieces comprising sheets of malleable material. The sequence of operations includes a sequence of bends, from a first through an Nth bend, for forming a finished workpiece from a stock sheet of malleable material. The system includes a setup planning mechanism for generating the sequence of bends and a setup subplan that includes information regarding the manner in which the bending apparatus is to be set up before commencing the first bend in the sequence of bends. In addition, the system includes a forwarding mechanism for forwarding the setup subplan, once generated, to a signalling device for signalling commencement of setup operations to be performed in accordance with the setup subplan. A finalize mechanism is further provided for generating detailed subplan information to complete the plan after the setup subplan has been generated. At least part of the detailed subplan information is generated after the commencement of setup operations has been signalled by the signalling device. The setup subplan may include one or more of the following types of information: information regarding the layout of tooling stages; information regarding tooling die and punch profiles to be utilized in the bending apparatus; positions of tooling stages along a die rail of the bending apparatus; information regarding what type of gripper to use for manipulating the workpiece through the bend sequence; and information regarding what type of repo gripper to use for holding the workpiece while a gripper changes it grasp on the workpiece in between bends of the bend sequence.
The forwarding device may include a device for forwarding instructions to a sequencer module which directs performance of automated setup operations on the bending apparatus. In addition, or in the alternative, the forwarding device may also, or in the alternative, create a visual representation of setup operations to be performed on the bending apparatus so that a human operator can thereby perform the setup operations.
In addition to the above-described systems and methods, the present invention may be directed to a system for performing setup operations on a bending apparatus so that the bending apparatus can be utilized to perform bending operations on workpieces comprising sheets of malleable material. The bending apparatus includes a die, a tool punch holding mechanism, and one or more tooling stages. Each tooling stage includes a die mounted on the die rail and a tool punch held by the punch holding mechanism. The system further includes a mechanism for receiving information regarding a location of each of the one or more tooling stages along the die rail, and a control mechanism for controlling a position of a guide member along at least one of a die rail and the tool punch holding mechanism based upon the received information so that at least one of the die and the tool punch can be aligned with reference to the guide member and so that the resulting tooling stage will be at a desired location along the die rail.
The control mechanism may be capable of positioning the guide member to be at a specified position along the die rail and to be within a certain distance from the die rail, whereby a die of a tooling stage to be aligned can be abutted against the guide member in order to properly position the tooling stage along the die rail. The guide member may include a backgage finger of a mechanism for performing backgaging when loading a workpiece into the bending apparatus.
In addition to the above-described Systems and methods, the present invention may be directed to a system for executing a plan for controlling a bending apparatus for bending workpieces comprising sheets of malleable material The plan includes a sequence of operations to be performed by the bending apparatus. A sensor-based control mechanism is provided for performing an operation, including moving a workpiece from one position to another, with the bending apparatus utilizing a sensor output to modify the movements of the workpiece. A measuring device measures an amount by which the movement of the workpiece was modified due to the sensor output, and a learned control mechanism performs the operation, including moving the workpiece from one position to another, without modifying the movement of the workpiece utilizing a sensor output. The learned control mechanism controls performance of the operation based upon the amount measured by the measuring device.
The above-listed and other objects, features, and advantages of the present invention will be more fully set forth hereinafter.